import React, { Component } from 'react'

export default class App4 extends Component {
    render() {
        return (
            <div>
                <A>
                    <B></B>
                </A>
            </div>
        )
    }
}

class A extends Component{
    render(){
        console.log(this.props)
        return(
            <div title="A">
            {this.props.children}
            </div>
        )
    }
}

class B extends Component{
    render(){
        return(
            <div title="A">
                我是B组件
            </div>
        )
    }
}